Honda Main Relay Failures

A special note on Hondas here. A very common and well-known problem with 90s Hondas is a failure of the main relay. The main relay sends power to the fuel pump and other systems on most Hondas of this vintage. If the main relay fails, it often causes a no-fuel-pressure condition, which leads to a no-start. I'm posting this in all caps because you need to burn this into your brain. HONDA FUEL PUMPS HARDLY EVER FAIL. Toyota is pretty much in the same boat. In 20 years of working on Hondas, I've replaced four fuel pumps, and two were aftermarket. That should tell you something. So if you have a Honda that doesn't have fuel pressure, look to the main relay and forget about the fuel pump. This video shows how to repair a main relay. This fix works and can save you the expense of purchasing a new one. Oh, don’t beat me up over my solder technique either. I’ve fixed my fair share of these relays and I have yet to have one come back. That’s not to say I couldn’t do a better job at soldering.

I'm not saying Honda fuel pumps never go bad, but if you suspect a bad fuel pump in a Honda, be sure to check for power on the yellow wire and ground at the black wire at the connector to the fuel pump itself when you turn the key on. If you have power and ground when you cycle the key and the pump doesn't run, by all means, replace the fuel pump. But if you don’t have power and ground at the pump when you cycle the key, keep looking and leave the pump alone.